The long term objective of this proposal is to identify genetic markers for non-insulin dependent diabetes mellitus (NIDDM) in American Blacks. The study of genes which predispose to NIDDM in American Blacks is complicated by the presence of genetic admixture in this immigrant population. American Blacks are direct descendants of slaves from West Africa who arrived in this country 200-300 years ago. The hypothesis to be tested by this proposal is that genes which contribute to susceptibility to NIDDM are more prevalent in Nigerian diabetics, as a result of genetic admixture in American Blacks. The specific aim of this proposal is to build a database of DNA samples from non-diabetic and diabetic (NIDDM) West African Black Nigerians for the purpose of evaluating the role of various genes in the inherited susceptibility to NIDDM. Studies proposed during this grant period include 1) the identification of 150 Nigerian individuals with NIDDM and an equal number of age-, weight- and sex-matched non-diabetic controls, to establish a database and collect DNA samples on each individual, 2) to begin to identify suitable families for establishment of permanent cell lines for linkage analysis, and 3) evaluate variants of insulin and glucokinase genes, previously identified in American Blacks with NIDDM, in the Nigerian populations. It is anticipated that this planning grant will facilitate the establishment of an international collaborative effort which will be necessary to obtain the genetic material required for evaluating the inherited basis of NIDDM in American Blacks.